Electron Impact Fragmentation of Size Selected Ar n (n=4 to 9) Clusters

Lohbrandt, Petra; Galonska, R.; Kim, H. J.; Schmidt, M.; Lauenstein, Ch.; Buck, U.

doi:10.1007/978-3-642-56800-8_42

Cited by 14 publications

(8 citation statements)

References 30 publications

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“…Thus it is not surprising that rare gas clusters also provide ideal systems for investigating dynamical models of the detection mechanisms of weakly bound neutral clusters upon the interaction with photon or electron impact. These processes are known to be dominated by extensive fragmentation. − The first experimental results for size selected neutral clusters were published for Ar n clusters. − The dominant fragment channel for cluster sizes up to n = 9 was the dimer ion Ar 2 + , although the calculated minimum configuration was that of Ar 3 + . , The first quantitative calculation on the fragmentation probabilities confirmed the experimental findings 8 using mean field dynamics with DIM (diatomics in molecule) potential surfaces. In the meantime, much better calculations have been performed in which all potential surfaces close to the ground state and their couplings are taken into account …”

Section: Introductionmentioning

confidence: 68%

“…Either the detected ions are counted as a function of the deflection angle to derive angular distributions or the velocity is measured by TOF analysis of the scattered signal. In the early stage of the experiment, a different apparatus has been used. , The geometrical dimensions and thus the resolution were different compared to the one described here, but the mode of operation was the same.…”

Section: Methodsmentioning

confidence: 99%

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Electron Impact Fragmentation of Size-Selected Krypton Clusters

Steinbach¹,

Fárnı́k²,

Buck³

et al. 2006

J. Phys. Chem. A

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Clusters of krypton are generated in a supersonic expansion and size selected by deflection from a helium target beam. By measuring angular distributions for different fragment masses and time-of-flight distributions for fixed deflection angles and fragment masses, the complete fragmentation patterns for electron impact ionization at 70 eV are obtained from the dimer to the heptamer. For each of the neutral Kr(n) clusters studied, the main fragment is the monomer Kr(+) ion with a probability f(n)(1)> 90%. The probability of observing dimer Kr(2)(+) ions is much smaller than expected for each initial cluster size. The trimer ion Kr(3)(+) appears first from the neutral Kr(5), and its fraction increases with increasing neutral cluster size n, but is always much smaller than that of the monomer or dimer. For neutral Kr(7), all possible ion fragments are observed, but the monomer still represents 90% of the overall probability and fragments with n > 3 contribute less than 1% of the total. Aspects of the Kr(n) cluster ionization process and the experimental measurements are discussed to provide possible reasons for the surprisingly high probability of observing fragmentation to the Kr(+) monomer ion.

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Section: Introductionmentioning

confidence: 68%

Section: Methodsmentioning

confidence: 99%

Electron Impact Fragmentation of Size-Selected Krypton Clusters

Steinbach¹,

Fárnı́k²,

Buck³

et al. 2006

J. Phys. Chem. A

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“…Only a relatively small fraction of the electron energy remains in the cluster excitation. For example, for Ar clusters, it has been shown, that only about 1‐5 eV excess energy remains in the internal excitation of the cluster contributing to its fragmentation . Thus the electron ionization can, in some cases, be a relatively gentle process and fragment the cluster even less than the photoionization at lower photon energies .…”

Section: Cluster Ionization For Mass Spectrometrymentioning

confidence: 99%

“…In 1980s, a neutral cluster size selection based on elastic scattering of the clusters with secondary helium beam was developed. 72,73 This method has been used mainly to investigate the fragmentation after electron ionization of small rare gas clusters, [74][75][76] and some molecular clusters, for example, water, ammonia, hydrocarbon clusters, etc. 77,78 Besides, the same scattering principle enabled vibrational IR spectroscopy of size selected neutral clusters in molecular beams.…”

Section: Cluster Sizementioning

confidence: 99%

“…For example, for Ar clusters, it has been shown, that only about 1-5 eV excess energy remains in the internal excitation of the cluster contributing to its fragmentation. 74 Thus the electron ionization can, in some cases, be a relatively gentle process and fragment the cluster even less than the photoionization at lower photon energies. 157 It has to be considered that an important contribution to the cluster fragmentation comes from the change in the cluster geometry after the ionization, and from the intracluster ion-molecule reactions.…”

Section: Nanocalorimetrymentioning

confidence: 99%

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Mass spectrometry of aerosol particle analogues in molecular beam experiments

Fárnı́k

Lengyel

2017

Mass Spectrometry Reviews

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Nanometer-size particles such as ultrafine aerosol particles, ice nanoparticles, water nanodroplets, etc, play an important, however, not yet fully understood role in the atmospheric chemistry and physics. These species are often composed of water with admixture of other atmospherically relevant molecules. To mimic and investigate such particles in laboratory experiments, mixed water clusters with atmospherically relevant molecules can be generated in molecular beams and studied by various mass spectrometric methods. The present review demonstrates that such experiments can provide unprecedented details of reaction mechanisms, and detailed insight into the photon-, electron-, and ion-induced processes relevant to the atmospheric chemistry. After a brief outline of the molecular beam preparation, cluster properties, and ionization methods, we focus on the mixed clusters with various atmospheric molecules, such as hydrated sulfuric acid and nitric acid clusters, N O and halogen-containing molecules with water. A special attention is paid to their reactivity and solvent effects of water molecules on the observed processes.

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Strong fragmentation of large rare gas clusters by high energy electron impact

Schütte¹,

Buck²

2002

International Journal of Mass Spectrometry

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Electron Impact Fragmentation of Size Selected Ar n (n=4 to 9) Clusters

Cited by 14 publications

References 30 publications

Electron Impact Fragmentation of Size-Selected Krypton Clusters

Electron Impact Fragmentation of Size-Selected Krypton Clusters

Mass spectrometry of aerosol particle analogues in molecular beam experiments

Strong fragmentation of large rare gas clusters by high energy electron impact

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